Playback is BLACK, audio OK.. what is the problem... not codec?

Hi,
I have recordings in Vineyard’s proprietry /mcg format that are very important to me.

I have the Vineyard player, but it only works successfully on certain PC’s. I’ve seen it work on Windows XP, XP Pro, Windows 7... but it doesn’t work on my PC at home.

Why?

Symptoms.
The recording opens and plays, and the audio is fine. But the video stays black with no picture.

I have downloaded everything I can think of...
- K-Lite codec pack (Mega)
- Itunes
- Real player
- Adobe Flash
- Microsoft DirectX
- VLC media player

all hoping that they will have something that the player needs...

However, it PLAYS the video, It is just black.. so I am beginning to think that it isn’t the codec that I need... but what does it need???